Miniaturized Nanocomposite Piezoelectric Microphones for UAS Applications
ARMY AVIATION AND MISSILE RESEARCH DEVELOPMENT AND ENG CTR REDSTONE ARSENAL AL
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Recent advances in microfabrication and nanoscale material synthesis have enabled a new generation of sub-mm piezoelectric microphones with the sensitivity of larger acoustic sensors. The piezoelectric approach enables new applications and platforms such as collision avoidance on UAS due to environmental damage resistance, small size, ability to flush mount and zero power supply requirements. In this paper we will present our latest development efforts to incorporate nanostructured piezoelectric material into a working microfabricated microphone. Further, we will discuss the unique challenges that must be overcome to package these sensors in arrays for a UAS platform. This paper presents the latest results from our development efforts. Utilizing lumped element and finite element modeling and composite material analysis, we designed a series of microphones with diameters ranging from 100 um to 800 um. A microfabrication process flow that incorporates a technique for integrating ZnO nanorods into a polymer diaphragm was then developed. Sensors were fabricated, released, and packaged on printed circuit boards in preparation for acoustic and electrical testing. Preliminary tests indicate successful fabrication with a flexible diaphragm, consistent electrical properties dielectric constant and loss tangent and measureable piezoelectric activity. Sensor characterization results show performance in line with theoretical predictions. Additional tests are currently underway using specially designed test structures to quantify material parameters such as Youngs modulus, density and residual stress.
- Electrical and Electronic Equipment
- Acoustic Detection and Detectors